Is Your Blood Pressure Under Control?

A middle aged woman visits her doctor due to high blood pressure read­ings. After three blood pressure measurements on three separate occasions, it was still higher than 140/90 millimetres of mercury. In­cidentally, this is the crite­ria set by the World Health Organization (WHO) in de­termining whether a person has high blood pressure. A high BP reading is called hypertension. What should be done next?

In this situation, doctors would normally assess for total cardiovascular risk, referring to her chances of having angina, heart attack or stroke in five years. In Australia, doctors use the Australian Absolute Cardi­ovascular Risk Calculator (www.cvdcheck.org.au). You may actually supply the needed information and it will calculate your risk straight away. More than 15% risk makes one high risk of developing heart, stroke and blood vessel dis­ease (cardiovascular dis­ease) in the next five years. Knowing your risk is to your advantage. If it turns out that you are on the high risk category, you can start to do something, perhaps undergoing some life style changes (diet, exercise, smoking, alcohol, stress) that could change the pen­dulum in your health’s fa­vour.

It may be a good start but it is not applicable for everyone. An Australian medical publication Check (July 2014) enumerates the conditions in which doctors should not use the above calculator:

Established cardiovascu­lar disease

• Diabetes and age >60 years

• Familial hypercholes­terolaemia

• Serum total cholesterol above 7.5 mmol/L

• Severe hypertension (systolic ≥180 mmHg, di­astolic ≥110 mmHg)

• Diabetes and microalbu­minuria

• <45 mL/min/1.73m2 or persistent proteinuria

What is of prime impor­tance when someone has persistently elevated blood pressure? Of course, you need to see your doctor to monitor your situation. Aside from assessing for cardiovascular risk, your GP would like to know the course and severity of the condition and whether it is already affecting your organs (kidney, heart, eyes, etc). Your GP may also want to know what medi­cations you are taking since there is a long list of drugs that can cause elevated blood pressure. The list includes over-the-counter drugs plus herbal formu­lations sourced from the corner Chinese medicinal shop.

He would be interested to know your diet (salty, junk, refined food), smoking and drinking history. Do you have time for exercise? Is your weight under control? What type of job do you do? Knowing what type of work is important since anxiety, stress and low mood may have a negative effect on our blood pres­sure.

A doctor’s assessment of someone with high blood pressure is not com­plete without doing some physical examination. Ac­cording to a recent issue of BMJ (British Medical Journal), included in this clinical exam are the fol­lowing:

•Fundoscopy for evidence of papilloedema or retinal haemorrhage

•Observation of neck veins. If these are distended it could indicate a raised jugular venous pulse, which is a sign of congestive cardiac failure

•Assessment of the apex beat to look for left ventricular hypertro­phy

•Auscultation of the heart for murmurs (in­dicating valve disease or cardiac failure)

•Palpation of the radial, popliteal, and foot pulses. Weak or absent pulses in the lower limbs may indicate peripheral vascular disease

•Assessment of the ankles and sacrum for any evidence of oedema

• A u s c u l t a t i o n of the carotid arteries for bruits (may indicate carotid stenosis, which carries an increased risk of a stroke).

Before doctors finally conclude that someone has hypertension, he wants to make sure that it is not due to technical problems like technique of taking blood pressure. Is the patient us­ing the right BP cuff, not too small or not too big? A small for the arm BP cuff may overestimate it and a big for the arm BP cuff may underestimate the ac­tual BP reading.

Have you heard of white coat hypertension? This is a situation where blood pressure goes when it is taken in a surgery or medi­cal clinic. However, when it is done at home, no problem, it is normal and stable. When this happens, the doctor may suggest an ambulatory BP monitoring (ABPM) where you are hooked up to a BP appara­tus that measures your BP for a day. If the BP read­ings are normal outside of the medical clinic, then the BP rise when taken in a clinic is due to anxiety and nervousness, not be­cause of any medical issue. Those who don’t want to use a gadget for 24 hours may avail themselves of home BP monitoring wherein BP readings are done at home with an ordi­nary BP measuring device. The digital version is the popular home BP device since it is user-friendly.

So if you are taking your blood pressure accurately, have no white coat hyper­tension and takes your anti-hypertensive medication/s regularly, and yet your blood pressure is still far from the normal range, then it is time to do some further investigation. If the kidneys are not doing well, your doctor may request simple urine microscopy/ culture, special urine test (urinary albumin-to-cre­atinine ratio), full blood count, serum biochemis­try, estimated GFR (glo­merular filtration rate), thyroid function tests, fasting lipids, and plasma aldosterone-to-renin ratio. To check whether the left side of the heart is bigger than normal, your doctor will do electrocardiography (ECG).

Majority of high blood pressure (95%) is termed essential, the cause being unknown. But 5% of hy­pertension cases belong to a minority group called secondary hypertension. These cases are sometimes referred to as resistant hypertension. Even with the use of at least three anti-hypertensive medica­tions (includes a diuretic), BP readings are still over 140/90 mm Hg for at least a month. If this is the case, it is time to think of second­ary hypertension (chronic kidney disease, Cushing’s syndrome, primary aldos­teronism, thyroid disorder and phaeochromocytoma). To determine the actual condition behind these secondary causes of high blood pressure, more spe­cialised investigations may be in order. Your GP may even decide to send you to some specialist (kidney specialist, endocrinologist) for further assessment and management.

For the usual drug therapy of hypertension, there are five classes of medications that are utilised by doc­tors today: ACE inhibitors, ARBs, calcium channel blockers (CCBs), thiazide diuretics and beta block­ers. Doctors follow an al­gorithm in deciding step by step what medications to use. Ordinarily, s/he starts with either an ACE inhibi­tor or ARB. Some experts favour CCB for those with Afro-Carribean ancestry. If either ACEI or ARB is not doing the job well, your GP may add CCB. Next in line is a thiazide diuretic. Last in the line is BB. These are the first group of anti-hypertensive medications.

There is a second group but usually when a pa­tient’s high blood pressure is still far from ideal even with 3 anti-hypertensive medications, it could be time to refer the patient to a specialist who may add a fourth and fifth medication (spironolactone, hydrala­zine, alpha blocker, etc).

As high blood pressure is a risk factor for heart dis­ease and stroke, monitor­ing it regularly and main­taining a healthy lifestyle are key factors that could put it under wraps. Watch­ing your diet, exercising regularly, smoking ces­sation, moderate alcohol intake and living a stress-free life (as much as possi­ble) can make a difference in shielding you from the dreaded consequences of long standing hyperten­sion- heart disease and stroke. If you have dif­ficulty normalising your blood pressure, talk to your doctor. He will rec­ommend both conservative measures and pharmaceu­tical formulations for you to have decent blood pres­sure readings.